AC: Abbreviation for Alternating Current.
Access Bus. A slow speed cable interface used on personal computers. Access bus is based in the I2C bus and is a serial interface. The interface consisted of 4 wires; serial data, serial clock, and power [+5 volt] and ground.
AC Coupling: The coupling of of one circuit to another through a capacitor or other device.
ACK: Abbreviation for acknowledge character.
Acknowledge character: [ACK] A transmission control character transmitted by the receiving station as an affirmative response to the sending station. Note: An acknowledge character may also be used as an accuracy control character.
Acquisition time: In a communications system, the time interval required to attain synchronism. In satellite control communications, the time interval required for locking tracking equipment on a signal from a communications satellite.
Address field: The portion of a message that contains the source-user address and the destination-user addresses. Note: In a communications network, the address field is usually contained within the message header portion of the message. A message usually consists of the message header, the user data, and a trailer.
AGP Bus. The Accelerated Graphics Port [AGP] bus was developed in 1995, with version 1 of the specification released in 1996. The interface was found on IBM compatible computers as a video expansion bus. This was a point-to-point interface, so the bus ran from the motherboard chip-set to the expansion slot connector. The final version of the spec was released as AGP 8x in 2002 and ran with a through-put of 2.1GBps. In 2005 the PCIe bus interface was released and obsoleted this interface for new [high-end] designs.
Ambient Temperature: The surrounding temperature such as the temperature of air surrounding a conductor in a compartment or within a piece of equipment. [Environmental Alarm Unit Manufacturers]
ASCII: Acronym for American Standard Code for Information Interchange. The standard code used for information interchange among data processing systems, data communications systems, and associated equipment in the United States. Note 1: The ASCII character set contains 128 coded characters. Note 2: Each ASCII character is a 7-bit coded unique character; 8 bits when a parity check bit is included. Note 3: The ASCII character set consists of control characters and graphic characters. Note 4: When considered simply as a set of 128 unique bit patterns, or 256 with a parity bit, dis-associated from the character equivalences in national implementations, the ASCII may be considered as an alphabet used in machine languages. Note 5: The ASCII is the U.S. implementation of International Alphabet No. 5 (IA No. 5) as specified in CCITT Recommendation V.3.